Description

On 17 January, 2004 a Cessna 208 Caravan operated by Georgian Express, took off from Pellee Island, Ontario, Canada, at a weight significantly greater than maximum permitted and with ice visible on the airframe. Shortly after take off, the pilot lost control of the aircraft and it crashed into a frozen lake.

Synopsis

The following is an extract from the official accident Report published by the Transportation Safety Board (TSB) of Canada:

“[…] Cessna 208B Caravan […] was on a flight from Pelee Island, Ontario, to Windsor, Ontario, with one pilot and nine passengers on board. The aircraft took off from Runway 27 at approximately 1638 eastern standard time and used most of the 3300-foot runway for the take-off run. It then climbed out at a very shallow angle while turning north over the frozen surface of Lake Erie toward Windsor. The aircraft struck the surface of the lake approximately 1.6 nautical miles from the departure end of the runway. All 10 persons on board were fatally injured.”

The Report states that prior to the accident and after completing the previous flight, concerns were raised to the pilot about the accumulation of ice. In response:

“[…] The pilot was observed to visually check the leading edge of the wing; however, he did not voice any concern and proceeded with loading the passengers and cargo.”

Furthermore, the Report describes the responsibilities of the pilot under the self-dispatch program, which include the completion of weight and balance calculations before each flight. Weight and balance calculations for the accident flight were not made. The Report uncovers that:

"The maximum allowable take-off weight for the Cessna Caravan is 8750 pounds (cargo pod installed); 8550 pounds if flying into known icing conditions. On the occurrence flight, using the actual weight of the occupants, the calculated take-off weight was 9820 pounds, 1270 pounds over the maximum allowable weight in icing conditions. This represents an overweight condition of about 15 per cent."

In the Flight Performance section, the Report states:

"[…]For flights in icing conditions above the maximum gross take-off weight, stall and controllability speeds are unknown and unpredictable.

Ice accumulation on an aircraft wing decreases lift, increases drag, and reduces the angle of attack (AOA) at which the maximum lift coefficient occurs. The aircraft will stall at a lower AOA, and the stall warning system will provide a reduced margin of safety compared to the margin of safety with a clean wing. The magnitude of the loss of lift will be airfoil dependent. The Cessna Caravan airfoil has been shown to be very sensitive to ice accumulation, and the loss of lift can exceed 50 per cent. “

The Cause and the contributory factors to the accident were given as:

• At take-off, the weight of the aircraft exceeded the maximum allowable gross take-off weight by at least 15 per cent, and the aircraft was contaminated with ice. Therefore, the aircraft was being flown significantly outside the limitations under which it was certified for safe flight.

• The aircraft stalled, most likely when the flaps were retracted, at an altitude or under flight conditions that precluded recovery before it struck the ice surface of the lake.

• On this flight, the pilot’s lack of appreciation for the known hazards associated with the overweight condition of the aircraft, ice contamination, and the weather conditions was inconsistent with his previous practices. His decision to take off was likely adversely affected by some combination of stress and fatigue.

Two Safety Recommendations relating to aircraft loading were made as a result of the Investigation.

Related Articles

• HF - Human Factors, Fatigue;
• WX - In-Flight Icing; Freezing Rain;
• GND - Aircraft Ground De/Anti-Icing, De/Anti-Icing Code, Holdover Time (HOT);
• LOC - Loss of Control, Stall;

Further Reading

For further information see the full accident report published by the TSB.

NTSB Safety Alerts on General Aviation risks

• Safety Alert 19 - Prevent Aerodynamic Stalls at Low Altitude
• Safety Alert 20 - Reduced Visual References Require Vigilance
• Safety Alert 23 - Pilots: Manage Risks to Ensure Safety